POWER

With U.S. combined-cycle plants increasingly being cycled—rather than being run continuously, as they were designed to do—owner/operators worry that units expected to last two or three decades may survive only a few years without an expensive overhaul. Cycling takes as much of a toll on heat-recovery steam generators as it does on gas turbines. Whether you’re procuring a new HRSG or adapting an existing one for cycling service, robust design features should be what you’re looking for.

The U.S. power generation industry is changing at warp speed, via regulatory changes, consolidation, mergers, and sales of assets at yard-sale prices. New players have entered the market and become major players overnight, while several mainstays have gone bankrupt. Though many of the latter blamed high gas prices for their woes, well-diversified merchants enjoyed a record year. Whatever changes are in store for the business of combined-cycle generation, you can be sure that innovations in plant design and O&M such as those described in this special section will keep pace with them.

Designers of heat-recovery steam generators are using computational fluid dynamics software as one tool to reveal the invisible forces affecting the flow over, under, around, and through structures such as inlet ducts, distribution grids, and guide vanes.

Copyright 2006 Platts, a Division of the McGraw-Hill Companies. All rights reserved. 800-PLATTS-8. Data Source: Platts Energy Advantage www.maps.platts.com

A multitude of variables must be accounted for during the design and development of a wet-stack flue gas desulfurization system. The five-phase process detailed below has proven effective on more than 60 wet-stack system design studies. A basic understanding of these concepts will help inform early design decisions and produce a system amenable to wet operation.

Increased cycling of combined-cycle plants has made precise control of attemperator spray water within heat-recovery steam generators more important if damage to their hardware and piping is to be avoided. Complicating the issue is the industry’s still-limited experience with cycling and the fact that demands on the attemperator and turbine bypass of cycled plants are more stringent than those on baseloaded units.

Focus on O&M

I couldn’t help but marvel at the synchronicity of two unrelated events over the past few weeks. The first, on January 12, was the rare cancellation of a major military acquisition program with problems called "too expensive to fix." It takes an Act of Congress to kill most military contracts due to the pork flowing […]

Focus on O&M

Nearly five years ago, a major IPP began standardizing steam cycle chemistry feed, control, and monitoring across its combined-cycle fleet. This article discusses the steps taken, the costs incurred, and the technical and financial benefits achieved. Although the project focused on non-cogeneration plants, the findings detailed below are broadly applicable to other kinds of plants. However, the specific implementations (especially of the chemistry standards) described may have to be modified slightly for application to cogen plants.

Focus on O&M

The jury is still out on the economic and technical feasibility of burning gasified coal to generate electricity. Gasification technology has yet to be proven on a utility scale, especially with Powder River Basin coal as the feedstock. And on the generation side, there are more questions than answers about the capital cost and availability of integrated gasification combined-cycle (IGCC) plants. But with natural gas prices high and rising, it’s definitely worth examining whether it would be economically and technically feasible to convert the existing U.S. fleet of gas-fired combined-cycle plants to burn gasified coal.

Sliding-pressure, supercritical plants are all the rage. They generally include certain design features developed for markets and operating environments outside the U.S., where new coal-fired plants have been built in recent decades. U.S. market conditions are different, and considerable capital cost savings—with negligible operating cost differences—are possible if technology options are considered for the next wave of supercritical and ultra-supercritical steam plants.

In 2002, the Bush administration launched the Clean Coal Power Initiative in the hope that it would develop the missing technology piece of the cleaner energy puzzle. Four years and two rounds later, the U.S. electric power industry is seeing the first usable clean coal technologies emerge before its eyes.

Compared to most pieces of a power plant, refractory costs very little to install. Yet, if improperly manufactured, specified, stored, mixed, installed, cured, or dried, refractory may cause problems that can significantly decrease a plant’s operating efficiency and flexibility. Like Rodney Dangerfield, refractory design and installation deserve more respect.

The 35th birthday of the Environmental Protection Agency (EPA) passed last December 2 with little fanfare. EPA Administrator Stephen L. Johnson noted at the time that, "Over the last three and a half decades, through the use of innovative and collaborative approaches to environmental protection and a commitment to responsible stewardship, we have made remarkable […]

GE Energy’s latest "first" is in Turkey, where the Frame 6C gas turbine-generator—a younger cousin of the popular Frame 6B—has made its commercial debut. The turnkey 130-MW combined-cycle plant, called the GE206C, comprises two 40-MW Frame 6Cs, one GE steam turbine-generator, two heat-recovery steam generators, and a distributed control system. The gas-fired plant (Figure 1), […]

New Jersey’s gaming mecca is hosting one of the largest hybrid (solar-wind) power plants in the world (Figure 3). The Jersey-Atlantic Wind Farm, with 7.5 MW of wind capacity and 0.5 MW from photovoltaic (PV) cells, is expected to generate 20,000 MWh annually. That should be enough to power an adjacent wastewater treatment plant operated […]

The 130-MW Yuncán  hydroelectric plant (Figure 4) has come online in Peru about 210 miles northeast of Lima. To show his support for the project, Peruvian President Alejandro Toledo Manrique attended the inauguration ceremony. Yuncán  was commissioned just 21 months after the Peruvian government awarded a 30-year contract to operate the plant to EnerSur, the […]

The long-awaited 41st edition of Babcock & Wilcox Co.’s (B&W’s) Steam: Its Generation and Use (Figure 5) is now available for ordering on the company’s web site, www.babcock.com. The release of the book is worth noting by power plant engineers for two reasons: The tome is the world’s longest continually published (since 1875) engineering text, […]

In "U.S. utilities driving for a license" (November/December 2005), we wrote that Bechtel Corp. is part of the UniStar consortium. Bechtel Corp. is not a member but is working for UniStar as a contractor.

Now that many U.S. selective catalytic reduction (SCR) systems are in their fifth or sixth year of operation, a number of utilities are shifting their attention from implementing the technology to operating and maintaining it. Catalyst management and performance are key to the successful operation of any SCR system.

As an alternative to purchasing new catalyst, technological and economic advantages make a compelling case for regenerating rather than replacing the metal or ceramic that enables selective catalytic reduction systems to capture NO_x.

The Roosevelt Hotel in New York City was the site of the 2005 Platts Global Energy Awards (GEA). The seventh annual black-tie soiree was the most global ever. Some 400 top executives from more than two dozen countries on five continents gathered at the Roosevelt on December 1, 2005, to honor the energy industry’s "Best […]

The EUCG surveyed 72 separate installations of selective catalytic reduction (SCR) systems at coal-fired units totaling 41 GW of capacity to identify the systems’ major cost drivers. The results, summarized in this article, provide excellent first-order estimates and guidance for utilities considering installing the downstream emissions-control technology.

  The U.S. needs to add 600 to 800 billion cubic feet (Bcf) of natural gas storage capacity ASAP. Independent storage providers (ISPs) are the entities best equipped to build this needed infrastructure, but they continue to be restrained by anachronistic regulatory policies. The Federal Energy Regulatory Commission’s (FERC’s) December 2005 rule-making to modify its […]

CFB refractory repair; Upgrading conductivity monitoring; Low-cost maintenance of spinning reserve

FACILITIES MAINTENANCE Duck and cover! Tippi Hedren learned the hard way—in Alfred Hitchcock’s 1963 classic, "The Birds"—the damage that a flock of angry seagulls can do. But what do you do when 6,000 starlings suddenly invade your power plant? Hide the birdseed and run for cover! Like any conscientious company, PacifiCorp works hard at keeping its […]

For more than 70 years, Steam Plant Operation (Figure 3), published by McGraw-Hill Professional (like Platts, the publisher of POWER, a division of The McGraw-Hill Companies Inc.), has been the bible of steam plant system design, installation, operation, maintenance, and repair. The new eighth edition of this classic reference book is now available.   3. […]

The reliability of service to millions of electricity consumers from Puget Sound to Portland improved significantly with the completion of the 84-mile-long, 500-kV Grand Coulee–Bell transmission line (Figure 4). The new path removes a major bottleneck between Spokane and Grand Coulee Dam and points west.   4. Breaking the bottleneck. The Bonneville Power Administration’s 84-mile, […]